base: Do not allow MessagePumpObservers to consume events.

content/browser/web_contents/web_contents_view_aura.cc

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "content/browser/web_contents/web_contents_view_aura.h"
 
 #include "base/auto_reset.h"
 #include "base/command_line.h"
 #include "base/file_util.h"
 #include "base/metrics/histogram.h"
@@ skipping 173 matching lines @@
     registrar_.Add(this,
                    NOTIFICATION_WEB_CONTENTS_DISCONNECTED,
                    Source<WebContents>(contents));
   }
 
   virtual ~WebDragSourceAura() {
     base::MessageLoopForUI::current()->RemoveObserver(this);
   }
 
   // MessageLoop::Observer implementation:
-  virtual base::EventStatus WillProcessEvent(
-      const base::NativeEvent& event) OVERRIDE {
-    return base::EVENT_CONTINUE;
-  }
+  virtual void WillProcessEvent(const base::NativeEvent& event) OVERRIDE {}
   virtual void DidProcessEvent(const base::NativeEvent& event) OVERRIDE {
     if (!contents_)
       return;
     ui::EventType type = ui::EventTypeFromNative(event);
     RenderViewHost* rvh = NULL;
     switch (type) {
       case ui::ET_MOUSE_DRAGGED:
         rvh = contents_->GetRenderViewHost();
         if (rvh) {
           gfx::Point screen_loc_in_pixel = ui::EventLocationFromNative(event);
@@ skipping 1301 matching lines @@
       event.location(),
       gfx::Screen::GetScreenFor(GetNativeView())->GetCursorScreenPoint(),
       ConvertAuraEventFlagsToWebInputEventModifiers(event.flags()));
   if (drag_dest_delegate_)
     drag_dest_delegate_->OnDrop();
   current_drop_data_.reset();
   return ConvertFromWeb(current_drag_op_);
 }
 
 }  // namespace content